Transducer selection guide

user1697292

Other Parts Discussed in Thread: TDC1000

I am trying to design a diesel level detector using TDC1000. Because the tank is made of metal and the bottom side is very thick.

I found the your EVM board SMD10T2R111 is suggested for water measurement. Is it still suitable for diesel level in a tank. Which transducer should I use? 1Mhz or 2Mhz?

Another question is I found SMD10T2R111 is not a 1Mhz one. The frequency is 215 KHz±5 KHz.

over 9 years ago

0 user1697292 over 9 years ago

Prodigy 80 points

Also I found there are Ultrasonic Flow Sensors, 1MHz from steminc web site. What's the difference between this one and the module used on EVM board. Can I use this one for level detection?

0 AmyLe over 9 years ago

TI__Intellectual 1635 points

Hi,
How large is the tank that you are measuring? What kind of level accuracy are you looking for? And how thick is the tank?
In general, I think using a 1MHz should be ok, and you have to use the SMD10T in the axial mode to get 1MHz; its radial mode is indeed 215kHz.

0 AmyLe over 9 years ago in reply to user1697292

TI__Intellectual 1635 points

Can I get a part number or link to the ultrasonic flow sensor from steminc's web site? Thanks.

0 user1697292 over 9 years ago in reply to AmyLe

Prodigy 80 points

SMD10T2R111

http://www.steminc.com/piezo/PZ_SpecSheet.asp?PZ_SM_MODEL=SMD10T2R111

I found another real 1Mhz one and I think it should be the real part used with TDC1000

SMD15T21R111WL

http://www.steminc.com/PZT/en/piezo-ceramic-disc-1-mhz

0 user1697292 over 9 years ago in reply to AmyLe

Prodigy 80 points

The size of tank is 700mm(L)*150mm(W)*500mm(H). The thickness is from 5mm to 10mm. What's the different using different frequency? impact the accuracy?

0 user1697292 over 9 years ago in reply to AmyLe

Prodigy 80 points

1Mhz ultrasonic flow sensor
http://www.steminc.com/PZT/en/ultrasonic-flow-sensor-1mhz-send-receive

0 Daniele Simioni over 9 years ago in reply to AmyLe

Prodigy 105 points

Hi Amy,
Do you have any guidelines in order to choose the best transducer (in terms of resonant freq and size) for each kind of application?
How can I individuate the best transducer to use with different type of liquid (i.e. water, milk, etc.), different accuracy, different size of tank and so on?

Thank you in advance.
Regards.

0 user1697292 over 9 years ago in reply to Daniele Simioni

Prodigy 80 points

Hi Amyle,

We are waiting for the answers. We have start the project on using TDC1000 but blocked on transducer selection.
Could you give some support? Could you reply ASAP?

0 Sergio over 9 years ago in reply to Daniele Simioni

TI__Expert 3835 points

Hi Daniele,

I don't know if there is a guideline available to select a transducer per type of liquid, but in general, transducers in the range of 1MHz to 2MHz are recommended for use in liquids, transducers in the range of 200kHz for gases, and transducers in the range of 40kHz for air.

Regards,
Sergio

0 Sergio over 9 years ago in reply to user1697292

TI__Expert 3835 points

user1697292,

The difference in frequency will mainly determine how well the sound propagates through a given medium. As it was mentioned, transducers resonating at a frequency of 1MHz-2MHz are typically used for liquid applications.

Piezoelectric transducers have two modes of resonance: axial mode and radial mode. The transducer used in the EVM has a radial mode resonance frequency of 215kHz and an axial mode resonance frequency of 1MHz.

Regards,
Sergio

0 Reiner Mende over 9 years ago in reply to Sergio

Prodigy 60 points

Hi Sergio,

I want to use TDC1000-TDC7200EVM in air with 40 kHz transducers.

How is it possible to drive the transducer in its resonant frequency as the clock devider allows only division factors in powers of 2?

Regards

Reiner

0 Sergio over 9 years ago in reply to Reiner Mende

TI__Expert 3835 points

Hello Reiner,

You can use an external clock with a frequency other than 8 MHz, such that the divider meets your needs.

If you are using the EVM, the most recent GUI allows the user, in the Setup tab, to select a clock generated by the on-board MCU. One such options is 1.2632 MHz, when divided by 32, results in 39.475 kHz.

Best regards,
Sergio

0 Mahendra Gunawardena over 9 years ago in reply to Sergio

Expert 1780 points

Recently I have been researching about axial and radial modes. Some good infomation can be found here

engineering.stackexchange.com/.../110

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Transducer selection guide